The regional director stressed that exposure to extreme heat "often exacerbates pre-existing health conditions" and noted that "individuals at either end of life's spectrum - infants and children, and older people - are at particular risk".
Responding to a query by AFP, WHO Europe explained that the figure is a preliminary estimate based on reports by national authorities, and that the toll had "already increased and will increase further over the coming days".
The true number of deaths linked to the heatwave won't be known for weeks, he said, adding "this scorching summer season is barely halfway done".
"Ultimately, this week's events point yet again to the desperate need for pan-European action to effectively tackle climate change," Kluge said.
The regional head of the UN health body said governments need to demonstrate will and leadership in implementing the Paris Agreement, which set the goal of limiting end-of-century warming to two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels -- and preferably not beyond 1.5C.
He said that members of the WHO's European region -- 53 countries and regions including several in Central Asia -- "have already demonstrated that they can work together on urgent threats to global health," and that it was "time for us to do so again."